A menstrual period typically lasts around 2–7 days, but sometimes it can last longer. This can be due to birth control and some health conditions, including endometriosis.

Occasionally, a period may take longer than usual to stop. There are several potential reasons for this, including the use of birth control and the presence of underlying health issues.

In this article, we cover potential reasons why a period may not stop and how to treat it.

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Some people experience bleeding during ovulation, when the ovaries release an egg. In most cases, ovulation will produce only slight spotting and is not a significant cause for concern.

When it occurs toward the end of a period, spotting from ovulation can make it seem like the period lasts longer than usual.

A healthcare professional can insert an intrauterine device (IUD) into the uterus to help prevent pregnancy. The two main types of IUD, hormonal and nonhormonal, can both cause abnormal bleeding.

Irregular periods are common after IUD insertion. As well as potentially causing longer periods, IUD placement can also cause periods to be lighter, shorter, or stop them altogether.

Hormonal birth control pills alter the body’s natural hormone levels. Although many people use hormonal contraceptives to shorten or regulate their periods, they can result in bleeding at times when a person is not expecting a period.

Abnormal periods are common during the first few months of taking a new hormonal medication. However, if they continue to occur after several months or become bothersome, speak to a doctor about switching birth control methods.

A doctor may recommend a different type of hormone — such as switching from a progestin-only pill to one that also contains estrogen — or they may suggest a different brand.

The thyroid gland is responsible for regulating a variety of hormones in the body. For females, this includes hormones associated with the menstrual cycle.

If a person has an underactive or overactive thyroid, they may experience long periods or ones that seem as though they will not stop.

Thyroid problems can also cause very light periods, several months without a period, and early menopause.

A simple blood test is often enough to diagnose problems with the thyroid. A doctor can then prescribe medications to help correct the hormone imbalance.

Learn more about an absence of menstruation, known as amenorrhea, here.

Polycystic ovary syndrome (PCOS) occurs when cysts frequently grow on the ovaries. PCOS can affect hormone levels and fertility.

Symptoms of PCOS include:

Endometriosis is a condition in which tissue that is similar to the tissue that lines the uterus grows outside of the uterus.

This tissue can swell and bleed in response to hormones, just as the uterine lining does during a period. Endometriosis lesions cannot exit the body, however, so they may result in pain and other complications, such as adhesions and cysts.

Symptoms of endometriosis can include:

Fibroids are muscular, usually benign tumors that form on the uterus wall. Polyps are red growths on the lining of the uterus.

Both are common problems that can cause heavier or longer-than-normal periods to occur.

Pregnancy loss, or miscarriage, often causes bleeding or spotting. This bleeding can be light or heavy and may last anywhere from a few hours to a few weeks. In some cases, pregnancy loss can occur before a person realizes they are pregnant.

If a miscarriage is responsible for the bleeding, it is best to speak to a doctor to ensure there are no complications.

Some people experience spotting or light bleeding in early pregnancy. Bleeding may occur with or without other signs of pregnancy, such as nausea.

Abnormal bleeding and pelvic pain during pregnancy may indicate an ectopic pregnancy, which can cause serious complications.

A doctor can detect both regular and ectopic pregnancies using an ultrasound and blood test. Anyone who thinks they may be pregnant can also take a pregnancy test at home.

Though uncommon, someone experiencing a prolonged period may have an underlying blood disorder.

Blood disorders can cause heavy bleeding and long periods. Other symptoms of a blood disorder include:

  • anemia
  • heavy bleeding after surgery and childbirth
  • bleeding for more than 10 minutes during a nosebleed
  • bleeding for longer than 5 minutes after a cut
  • easy and frequent bruising

Though menopause often occurs between ages 45–55, the body’s hormone levels can start to change several years prior. This stage is called perimenopause.

During perimenopause, periods can be less or more frequent, as well as shorter or longer than usual.

Cervical cancer can cause abnormal bleeding, including between periods and after sexual activity. It can also cause periods that are longer and heavier than usual.

The human papillomavirus (HPV) is the primary cause of cervical cancer. HPV is very common and many people have it without knowing it, or without having any symptoms. Only a few types of HPV lead to cervical cancer.

Most symptoms of cervical cancer are similar to those of more common conditions, such as PCOS or endometriosis. It is important to attend regular Pap tests, which can help a doctor diagnose HPV or cervical cancer.

Cancer treatment options include surgery, chemotherapy, and radiation therapy.

Though most long periods will resolve on their own, if a person experiences any of the following symptoms, they should speak with a doctor:

  • periods that last for longer than 7 days
  • unexplained bleeding
  • unusual discharge
  • heavy periods
  • nausea, vomiting, or severe pain during a period
  • unexplained weight loss

Below are some commonly asked questions about a period that won’t stop.

What does it mean when a person’s period blood won’t stop?

If a person’s period blood won’t stop, this may mean:

  • they are ovulating
  • they have an intrauterine device (IUD)
  • they take hormonal birth control
  • they have thyroid problems
  • they have polycystic ovary syndrome
  • they are pregnant
  • they have a blood disorder

When should a person go to the hospital if their period won’t stop?

According to the Centers for Disease Control and Prevention (CDC), a person should seek medical help if they:

  • have menstrual bleeding that soaks through one pad or tampon per hour for several hours
  • pass blood clots that are larger than a quarter
  • are pregnant and experience heavy or prolonged bleeding, as this can signal miscarriage or an ectopic pregnancy
  • experience menstrual bleeding that lasts more than 7 days

Why have I been bleeding for over a month?

Potential reasons why a person has experienced prolonged menstrual bleeding include the following:

  • they have an intrauterine device (IUD)
  • they take hormonal birth control
  • they have thyroid problems
  • they have polycystic ovary syndrome

If a person has been bleeding for more than 7 days, they should seek urgent medical attention.

Why am I light bleeding for 2 weeks?

There are many reasons why a person might experience light menstrual bleeding, including:

  • perimenopause
  • an eating disorder
  • uncontrolled diabetes
  • hormonal birth control pills
  • certain medications

However, if a person has light bleeding that exceeds 7 days, they should speak with a doctor.

Having a light period that does not seem to stop is not usually a sign of a serious medical problem. However, if it is painful or bothersome, a person can speak to a doctor about possible solutions.

Having long periods frequently can indicate one of several potential conditions, such as endometriosis or uterine fibroids. A doctor can help diagnose and treat these conditions.

Often, taking hormonal birth control pills or switching the type of hormonal medication can help people find relief.